JP2002274423A - Front car body structure for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the impact load acting on an occupant by desirably lowering a decelerating speed of a car body by remarkably reducing the deformation load of a front side frame during a head-on collision of an automobile. SOLUTION: Front side frames 11, 11 are divided into front frames 50, 50 having impact absorption parts 52, 52, and rear frames 51, 51 to which the front frames 50, 50 are respectively slidably fitted, and fastened by bolts 55, 55, etc., and nuts 56, 56, etc. Rear parts of rear bolt holes 58, 58 are provided with holding parts 62 of the bolts 55, and slits 59 are formed at the rear parts of the holding parts. The fastening force of the bolts 55, 55, etc., and the breaking force of the holding parts 62, 62 are determined so that the rear bolts 55, 55 break the holding parts 62, 62, and are moved to the slits 59, 59 by the compressed load applied to the front side frames 11, 11 after the collapsed deformation of the impact absorbing parts 52, 52 are finished in collision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a front side frame provided at a front portion of an automobile so as to extend in a longitudinal direction of a vehicle body.

[0002]

2. Description of the Related Art Conventionally, as a front body structure of this kind of automobile, for example, as disclosed in Japanese Patent Application Laid-Open No. 2000-53022, the deformation mode of a front side frame is collapsed in the event of a frontal collision of the automobile. It is known that by switching from deformation to bending deformation, a relatively large deceleration is generated with respect to the vehicle body in the early stage of the collision, and then the vehicle body deceleration is temporarily reduced.

[0003] As shown in FIGS. 12 and 13, the left and right sides of a bumper reinforcement 101 extending in the vehicle width direction are provided at the front ends of front side frames 100, 100 provided on the left and right sides of the front part of the vehicle body, respectively. An oblique beam 1 that is attached to each of the front side frames 100 and 100 and that extends obliquely outward of the vehicle body from the center in the front-rear direction of the front side frames 100 and 100 toward the front.
02 and 102 are provided. The front ends of the oblique beams 102, 102 are spaced apart from the bumper reinforcement 101 by a predetermined distance in the front-rear direction, and when viewed from the vehicle front-rear direction, the vehicle of the bumper reinforcement 101 It is positioned so as to overlap with both ends in the width direction.

In this structure, the impact at the time of a frontal collision is first transmitted from the bumper reinforcement 101 to the front side frames 100, 100, and as shown in FIG.
The front end side of 100 undergoes crushing deformation with a relatively large deformation load. Next, bumper reinforcement 101
Both ends in the vehicle width direction are the oblique beams 102, 102
When a lateral load is applied via the oblique beams 102, 102 to the front end portions of the front side frames 100, the central portions of the front side frames 100, 100 are bent inwardly into the vehicle body and deformed thereafter. The load is relatively small. As a result, the vehicle body deceleration can be made to rise sharply at the beginning of the collision, and thereafter, the vehicle body deceleration can be lowered.

Here, the deceleration acts on the occupant at the time of collision due to the reaction force from a restraining means such as a seat belt for restraining the occupant. The occupant deceleration is extremely small. On the other hand, since a large deceleration acts on the vehicle body from the beginning of the collision, the relative movement distance between the occupant and the vehicle body gradually increases. The reaction force received from the motor becomes maximum, and a large impact load is received.

In the prior art, in order to reduce the impact load on the occupant, the deformation mode of the front side frame is switched just before the seat belt elongates to a maximum after a collision to lower the vehicle deceleration. ing.

[0007]

However, in the above-mentioned conventional structure, the power plant mounted between the pair of front side frames hinders the inward bending deformation of each of the front side frames. In this case, since the vehicle body deceleration cannot be lowered as described above, there is a problem that the maximum value of the occupant deceleration, that is, the impact load cannot be reduced as intended.

The present invention has been made in view of the above points, and an object of the present invention is to devise the structure of the front side frame to greatly reduce the deformation load of the front side frame during a collision. The purpose of the present invention is to reduce the impact load acting on the occupant by lowering the vehicle deceleration as intended.

[0009]

In order to attain the above object, according to the present invention, a front side frame is provided with a front member and a rear member in which the front member is slidably fitted in the vehicle longitudinal direction. When the front side frame is deformed at the time of a frontal collision of the vehicle, the front side member starts retreating with respect to the rear side member.

More specifically, according to the first aspect of the present invention, the front vehicle body includes a pair of front side frames each extending in the vehicle front-rear direction on both left and right sides of the vehicle body front portion and having a shock absorbing portion provided on the front end side. Assume the structure. The front side frame includes a front member having the shock absorbing portion, and a rear member fitted with the rear end of the front member slidably in the front-rear direction of the vehicle body.
The vehicle has a connecting portion for fixing the front member to the rear member, and the connecting portion is connected to the front side after the impact energy absorbing load in the impact absorbing portion reaches a set value when the vehicle collides from the front. Also, the fixed state of the rear member is released.

According to this structure, when an impact load is input to the front side frame in the event of a frontal collision of the vehicle, the impact energy is absorbed by the impact absorbing portion of the front member, and the vehicle body deceleration rises sharply, and the seat is decelerated. The belt stretches early and strongly restrains the occupant. After that, before the seat belt elongates to a maximum, the energy absorbing load in the shock absorbing portion reaches the set value, and the fixing state of the connecting portion to the rear member at the front member is released. Since the vehicle slides on the side member, the vehicle body deceleration is significantly reduced.

That is, the front member can slide relative to the rear member during the deformation of the front side frame, so that the deformation load can be greatly reduced.
When the seat belt is fully extended, the vehicle body deceleration is reduced at the intended timing, and the impact load on the occupant due to the reaction force of the seat belt can be sufficiently reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a regulating means for regulating the retreat of the front member so that a sliding distance of the front member with respect to the rear member is equal to or less than a set distance. And Thus, when the sliding distance of the front member with respect to the rear member becomes the set distance, the restricting means prevents the front member from retreating, the deformation load of the front side frame increases, and the vehicle body deceleration increases again. That is, the range in which the vehicle body deceleration is temporarily lowered during the deformation of the front side frame can be set by the restricting means.

According to a third aspect of the present invention, in the second aspect of the present invention, the coupling portion includes a fastening member for fastening the front member and the rear member, and a through hole through which a shaft portion of the fastening member passes in the rear member. And a slit which is provided in the vicinity of the through hole behind the vehicle body and is long in the vehicle front-rear direction.

Thus, the front member can be reliably fixed to the rear member by the fastening member. On the other hand, at the time of a frontal collision of the automobile, the shaft of the fastening member can be moved rearward along the slit along the vehicle body, so that the front member can slide with respect to the rear member. Further, at that time, the sliding resistance acting on the shaft portion of the fastening member can be changed by, for example, the sectional shape of the slit.

According to a fourth aspect of the present invention, in the second aspect of the present invention, a power plant is disposed between the pair of front side frames, and the coupling portion penetrates a front member and a rear member to form the power plant. It is provided with a pin member for fixing the member, and a detaching member for engaging with the power plant which retreats at the time of a frontal collision of the automobile and detaching the pin member from the front member or the rear member.

Thus, both members can be reliably fixed by the pin member penetrating the front member and the rear member. On the other hand, at the time of a frontal collision of the vehicle, the detachment member causes the pin member to detach from the front member or the rear member by retreating the power plant, so that the fixed state of both members can be reliably released.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the detachable member is rotatably supported by the front side frame and viewed along a direction in which the rotation axis extends. A lever member having at least two arm portions extending in different directions from the support portion, wherein a distal end side of a first arm portion of the lever member is connected to the pin member, and a distal end side of a second arm portion is the front side. It is configured to protrude from the frame toward the power plant and to be positioned at a predetermined distance rearward from the power plant.

With this configuration, at the time of a frontal collision of the vehicle, the power plant and the second arm portion of the lever member are engaged by the retreat of the power plant, and the lever member is displaced rearward of the vehicle body. Is rotated about a rotation axis. Accordingly, the first arm portion is displaced so as to detach the pin member from the front member or the rear member, so that the fixed state of both members can be reliably released. Further, since the engaging portion of the power plant and the engaging portion of the lever member are separated from each other by a predetermined distance, they do not come into contact with each other due to the swing of the power plant in a normal state.

According to a sixth aspect of the present invention, in the first aspect of the present invention, a sub-frame extending in the vehicle front-rear direction is disposed below the pair of front side frames, and the sub-frame is formed by a front member and The rear end of the front member is formed of a rear member fitted slidably in the front-rear direction of the vehicle body, and has a connecting portion for fixing the front member to the rear member. Then, when the fixed state of the connecting portion of the sub-frame at the connecting portion of the front side frame is released, the fixed state of the front and rear members is released.

In this configuration, since the sub-frames are provided below the pair of front side frames, the rigidity of the vehicle body at the front of the vehicle can be improved as a whole. Further, this sub-frame has the same structure as the front side frame, and when the front and rear members of the front side frame are released from the fixed state at the time of a frontal collision of the vehicle, the front and rear of the sub-frame are disengaged. Since the fixed state of the side members is also released, similarly to the invention of claim 1, the deformation load of the front side frame and the sub-frame during the deformation is significantly reduced, and the impact load on the occupant is reduced. Can be sufficiently reduced.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIGS. 1 to 5 show a front body structure of an automobile according to Embodiment 1 of the present invention. 1 and 2 are a diagram showing the structure of the right front side frame and a bottom view of the vehicle body, respectively.

As shown in FIG. 3, the vehicle has an engine room 1 on the front side and a power plant 4 including an engine 2 and a transmission case (for housing a transmission, etc.) 3 in the engine room 1. The front wheels (not shown) are driven by the power plant 4. Although not shown, the engine 2 of the power plant 4 is configured such that a plurality of cylinders are arranged in a straight line in a direction in which the crankshaft extends, and the engine 2 is placed laterally with respect to the vehicle body so that the crankshaft faces substantially in the vehicle width direction. The right side surface of the transmission case 3 is fastened to the left side surface of the cylinder block of the engine 2. Although not shown, an intake manifold, accessories and the like are attached to a front wall portion of the engine 2, and a radiator and a fan of the radiator are attached to a vehicle body in front of the intake manifold. Reference numeral 12 shown in FIG. 1 is a drive shaft for drivingly connecting the output shaft of the transmission case 3 and the front wheels.

The rear side of the engine room 1 is partitioned by a dash panel 5.
The rear side of the vehicle is a passenger compartment 6, and the lower side of the passenger compartment 6 is partitioned by a floor panel 7. This floor panel 7
From the lower end edge of the dash panel 5, it extends downward and inclines backward, and after reaching the lower end of the vehicle body, bends,
It is formed so as to extend substantially horizontally rearward therefrom. 2, only side sills 10 each having a closed cross-sectional structure extending along the edges are provided at both end portions of the floor panel 7 in the vehicle width direction.

The inside of the side sills 10, 10, along the lower surface of the floor panel 7,
A pair of floor frames 20 extending substantially parallel to 0 and 10;
20 are provided, and the floor frames 20 and 20 are provided.
Has a U-shaped cross section open at the top, and its upper end is welded to the lower surface of the floor panel 7. A substantially central position of the floor panel 7 sandwiched between the pair of floor frames 20, 20 extends from the front end to the rear end of the vehicle compartment 6.
The floor tunnel portion 21 is formed so as to bulge toward the side, and the front end side portion of the floor tunnel portion 21 bulges toward the front.

The dash panel 5 extends between the floor tunnel portion 21 and each of the floor frames 20, 20 from the inside of the floor frames 20, 20 to the outside of the body of the floor tunnel portion 21. Dash lower reinforcements 22 are provided on the lower end and the front end of the floor panel 7. Further, from the outside of the body of the left and right floor frames 20, 20 to the inside of the body of the side sills 10, 10,
Similarly to the dash lower reinforcements 22, 22, torque boxes 23, 23 welded to the dash panel 5 and the floor panel 7, respectively, are provided.

On both sides of the engine room 1 in the vehicle width direction, a front side frame 11 made of a steel plate extending from the dash panel 5 to the front of the vehicle body,
11 are provided. The pair of front side frames 11 has a substantially rectangular hollow cross section as a whole, extends forward from the lower end of the vehicle body along the inclined portion of the floor panel 7, and is vertically centered in the engine room 1. The front part of the power plant 4 is formed so as to bend in the vicinity of the power plant 4 and extend forward from the front end of the power plant 4 in a substantially horizontal direction.

The front side frames 11, 11 will be described in detail with reference to FIGS. FIG. 3 is a perspective view of the front part of the vehicle body as viewed from above, and FIG. 4 is an enlarged view of the front side frames 11, 11. FIG. 5 is a sectional view taken along line AA in FIG.

The front side frames 11, 11
As shown in FIG. 3, a front frame (front member) 5 is provided at an intermediate portion of the engine room 1 in the vehicle longitudinal direction.
0, 50 and a rear frame (rear member) 51, 51. Further, as shown in FIG. 5, the outer dimensions of the cross-section of the front frames 50, 50 are smaller than the inner dimensions of the cross-section of the rear frames 51, 51. The two frames 5 are fitted to the rear frames 51, 51 so as to be slidable in the vehicle longitudinal direction.
0, 50, 51, 51 are fixed respectively.

The front frames 50, 50 are formed so as to have substantially the same cross section from the front end to the rear end, and the rear end of the front frame 50, 50 viewed from the vehicle up / down and vehicle width directions. The frame 51 overlaps the front end of the frame 51 by a predetermined distance. On the other hand, on the front end sides of the front frames 50, 50, shock absorbing portions 52, 52 which receive a compressive load due to an impact at the time of a frontal collision and crush and deform in the vehicle longitudinal direction, thereby absorbing impact energy. Is provided. The shock absorbing parts 52, 52
The frame-side impact absorbing portions 53, 53 formed integrally with the front frames 50, 50 at the front end sides of the frame 0, 50, and the crash boxes 26, attached to the front end portions of the frame-side impact absorbing portions 53, 53, 26.

The crash boxes 26, 26 are formed so as to have a rectangular cross section that becomes smaller toward the front side, and have rectangular flange portions 24, 24 extending at the rear end in the vehicle width direction and the vehicle body vertical direction, respectively. Is provided.
The flange portions 24 of the crash boxes 26, 26,
24 are attached to flange portions 25, 25 of substantially the same shape provided at the front ends of the front frames 50, 50. The frame-side shock absorbing portions 53, 53 are formed with substantially elliptical beads which are long in the vehicle width direction and the vehicle body vertical direction on the upper surface and both side surfaces, so that crushing deformation at the time of collision is ensured. Period. On the other hand, beads similar to the frame-side impact absorbing portions 53, 53 are formed on the upper surface and both side surfaces of the crash boxes 26, 26.
The vehicle width direction ends of the bumper reinforcement 27 are fixed to the front ends of the bumpers 6 and 26, respectively. The load at which the crush deformation of the crash boxes 26, 26 and the frame-side impact absorbing portions 53, 53 ends will be described in detail later, but the fixed state of the front frame 50 and the rear frame 51 is released at the time of collision of the vehicle. The size is set so that

The rear frames 51, 51 are formed to have substantially the same cross section from the front end to the vicinity of the center in the vehicle longitudinal direction, while the vicinity of the center is As shown in FIG. 3, the outer wall portion of the vehicle body is recessed toward the vehicle body inward to form a concave portion so as to prevent interference with the front wheel during steering of the front wheel. The rear ends of the rear frames 51, 51 are respectively connected to the front ends of the floor frames 20, 20 provided on the lower surface of the floor panel 7.

Next, the structure of the connecting portion for fixing the front frame 50 and the rear frame 51 as described above will be described. The front and rear frames 50 and 51 pass through the overlapping portions in the vehicle width direction. 4 sets of bolts 55,5
, And nuts 56, 56,... As shown in FIG. 4, the four bolts 5
Two of the bolts 55, 55 are arranged side by side in the vertical direction of the vehicle body at the front end side of the overlapping portion, and the remaining two bolts 55, 55 are arranged at the rear end side of the overlapping portion. It is arranged in the same manner as the bolts 55 on the front end side.

The front bolts 5 are provided on the inner walls and the outer walls of the rear frames 51, 51, respectively.
As shown in FIG. 5, the bolt holes 57, 57 through which the holes 5, 55 pass are elongated holes in the vehicle longitudinal direction. On the other hand, the bolt holes 58, 58 through which the rear bolts 55, 55 penetrate in the respective walls of the rear frames 51, 51 on the inner side of the vehicle body and on the outer side of the vehicle body are circular. Slits 59, 59 long in the front-rear direction of the vehicle body are provided behind the rear bolt holes 58, 58 in the vehicle front-rear direction.
The rear bolt hole 58 is located at a position separated from the rear edge of the rear bolt hole 58 by a predetermined distance to the rear of the vehicle body. Further, the distance from the front edge of the front bolt holes 57, 57,... To the rear edge of the rear frame 51, and the distance between the front edges of the rear bolt holes 58, 58,. The distance to the trailing edge is the same distance. In addition, the front frame 5
The bolt holes 6 through which the four bolts 55, 55,.
0, 60,... Are provided.

When fixing the front frame 50 and the rear frame 51, first, the front frame 50 is fixed.
Is fitted into the rear frame 51, and both frames 5
Positioning is performed so that the corresponding bolt holes 57, 58, 60 of 0, 51 overlap each other. Then, washers 61, 61,... Are attached to the bolts 55, 55,..., Respectively, and bolt holes 57, 58, 60 of the front and rear frames 50, 51 are inserted from the inside of the engine room 1 To the rear frame 5
, And nuts 56, 56,... Disposed on the outer side of the vehicle body 1 and the bolts 55, 55,.
This is performed by screwing with 6, 56,.

When a compressive load is applied to the front side frame 11 in the vehicle longitudinal direction, the front frame 50 is fixed to the rear frame 51 by the fastening force of the bolts 55 and nuts 56. At the same time, the shaft of the bolt 55 is
The front frame 50 is fixed by the holding portion 62 between the rear bolt hole 58 and the slit 59.
That is, in the first embodiment, the timing at which the front frame 50 starts sliding can be set by the fastening force of the bolts 55, 55,... And the nuts 56, 56, and the breaking load of the holding portions 62, 62. Specifically, the timing of the start of the sliding is after the deformation of the shock absorbing portion 52 of the front frame 50 is completed.

The front side frame 11,
Numeral 11 supports the power plant 4 in the engine room 1 as shown in FIG. The vicinity of both ends in the vehicle width direction of the power plant 4 is mounted on the mounting member 1 with respect to the front side frames 11, 11, respectively.
It is elastically supported via 3 and 14. The mount members 13 and 14 include brackets 15 and 17 attached to the power plant 4 and brackets 16 and 18 attached to the rear frames 51 and 51 of the front side frames 11 and 11, respectively.

Next, the front side frame 11,
The perimeter frame 30 (sub-frame) arranged below 11 will be described. The perimeter frame 30 is made of a steel plate and supports the power plant 4, the steering device (only the output shaft 31 is shown in FIG. 1), and the like, and is integrally formed so as to form a substantially rectangular frame as a whole. It has a structure. The front member 32 on the front end side of the perimeter frame 30 is located near the front end of the rear side frame 51 of the front side frame 11, the front side of the front side frame 11, and the rear side frame 51 of the left side of the vehicle body. , And extends linearly in the vehicle width direction from the position directly below the rear frame 51 on the right side of the vehicle body. Further, the side member portion 3 having substantially the same cross section as the front member portion 32 extends from both left and right ends of the front member portion 32 toward the rear of the vehicle body.
3, 33 are provided.

Further, each of the side member portions 33, 33
A suspension cross member portion 34 having a cross section larger than the cross section of the front member portion 32 is provided at a position rearward by a predetermined distance from the front end portion of the two side member portions 3.
It is welded in a state of being bridged between 3,33. Also,
As shown in FIG. 1, the side member portions 33, 33
When viewed from the vehicle width direction, it is formed so as to extend substantially horizontally from the rear end portion to a substantially central portion in the front-rear direction, and is bent so as to incline upward at this central portion, and further along the inclination direction. Extending to the front end.

Although not shown, the suspension cross member portion 34 has front-wheel suspension arms attached to both ends in the vehicle width direction. The length of the suspension cross member portion 34 in the vehicle width direction is greater than that of the front member portion 32. It is getting shorter. Also, as shown in FIG.
When viewed from the vertical direction of the vehicle body, the front and rear parts 33, 33 are relatively gentle inclining from the front end to the substantially central part in the front-rear direction, so that the rear side is closer to the inside of the vehicle body. It is bent so as to be tightly inclined and extends to the rear end, and a bent portion protruding outward in the vehicle width direction is formed in the central portion.

In mounting the perimeter frame 30, the front end of each side member 33 is fixed to the rear frame 51 of each front side frame 11, while the rear end of the side member 33 is At a position on the rear side with respect to the dash lower reinforcements 22, 22, respectively.

More specifically, the perimeter frame 30 is attached to the left and right corners on the front side of the perimeter frame 30 so as to protrude upward from the upper surface of the corner while gradually sloping outward and in the vehicle width direction. Brackets 36, 36 are provided. The lower ends of the mounting brackets 36, 36 are welded to the perimeter frame 30, while the upper ends are provided with cylindrical portions 37, 37 whose axes extend in the vertical direction. A rubber bush (not shown) is fitted. Further, a pipe member (not shown) is fixed to the rubber bush so as to be coaxial with the cylindrical portions 37, 37, and bolts 38, 38 penetrating the pipe member in the axial direction are used to fix the rubber members. The upper end of the pipe member is fastened to the front end of the rear frame.

On the other hand, the perimeter frame 30 is attached to the dash lower reinforcement 2 at the rear end of the side member portions 33, 33 of the perimeter frame 30.
Attachment portions 39, 39 for attachment to 2, 2, 22 are provided, respectively. The mounting brackets 3 on the front side of the perimeter frame 30 are also provided on the mounting portions 39, 39.
Similarly to the upper end portions of the cylindrical portions 6, 36, cylindrical portions 40, 40 are provided, and rubber bushes (not shown) are fitted inside the cylindrical portions 40, 40. A pipe member (not shown) is fixed to the rubber bush, and a bolt 4
The upper end of the pipe member is fastened to the dash lower reinforcements 22, 22 by 1, 41.

Next, the deformation of the front side frames 11, 11 when the vehicle collides from the front will be described in detail with reference to FIG.

First, in the initial stage of the collision, as shown in FIG. 4A, the impact energy at the time of the collision (the input direction is indicated by an arrow in the figure) is transmitted through the bumper reinforcement 27 to the crash box. 26, 26 and the frame-side shock absorbers 53, 53, and each of them starts crushing deformation. On the other hand, the load for releasing the fixed state of the front frames 50, 50 with respect to the rear frames 51, 51 acts on the front side frames 11, 11 after the crushing deformation of the shock absorbing parts 52, 52 is completed as described above. Since the load is set, the front frames 50, 50 do not slide at this stage, and the vehicle body deceleration rises significantly. In other words, the shock absorbing characteristics of the shock absorbing portions 52, 52 are such that the holding portions 62, 62 are broken by the shock at the initial stage of the collision while the vehicle deceleration at the initial stage of the collision rises steeply, and Excessive impact is absorbed so that the fixed state of the side frames 50 and 51 is not released.

Subsequently, the crash boxes 26, 2
After the crush deformation of the frame 6 and the frame-side impact absorbing portions 53, 53, the compressive load (indicated by the arrow in FIG. 3B) on the front side frames 11, 11 in the vehicle longitudinal direction increases, and Is further increased. Then, as shown in FIG.
The fixed state of the rear frames 0, 50 with respect to the rear frames 50, 50 is released, and the front frames 50, 50 start sliding backward.

That is, after the shock absorbing portions 52, 52 are crushed, the sliding of the front frames 50, 50 is started, and the deformation load of the front side frames 11, 11 is greatly reduced, so that the vehicle body deceleration is temporarily reduced. , Can be lowered. At this time, since the front frames 50, 50 slide so as to enter the inside of the rear frames 51, 51, interference with the power plant 4 and other vehicle body-side members can be reliably avoided, and as intended. In addition, the deformation stroke can be secured while reducing the deformation load.

When the front frame 50 slides, the shafts of the front and rear bolts 55, 55,.
... and the slits 59, 59, ...
The front frame 50 can be reliably guided to the rear of the vehicle body.

Also, as described above, the distance from the front edge to the rear edge of the front bolt holes 57, 57,... Of the rear frame 51 and the slit from the front edge of the rear bolt holes 58, 58,. Since the distances to the rear edges 59, 59,... Are the same, when the front frame 50 slides, the shafts of the four bolts 55, 55,. .. And the rear edges of the slits 59, 59,..., And the sliding of the front frame 50 is reliably prevented. That is, the front bolt holes 57, 57,.
The rear edge portion and the rear edge portions of the slits 59, 59,... Serve as restricting means for restricting sliding of the front frame 50 with respect to the rear frame 51. Front side frame 1
It is possible to set a range in which the deformation loads 1 and 11 are reduced. Although not shown, a protrusion may be provided on the inner surface of the rear frame 51, for example, so that the rear end of the front frame 50 slides a set distance and abuts on the inner surface of the rear frame 51.

FIG. 7 shows a vehicle body deceleration characteristic a (solid line) and an occupant deceleration characteristic b (dashed-dotted line) of the vehicle according to the first embodiment, and a comparative example without the front vehicle body structure. FIG. 7 is a characteristic diagram showing a vehicle body deceleration characteristic c (broken line) and an occupant deceleration characteristic d (two-dot line) in comparison. In this characteristic diagram, the horizontal axis represents the amount of crushing of the vehicle body, and the vertical axis represents deceleration.

First, the deceleration characteristics c and d of the vehicle body and the occupant of the comparative example will be described. The vehicle body deceleration characteristic c rises in the early stage of the collision and the vehicle body collapses and deforms while maintaining a substantially constant deceleration. At the end of the collision, the power plant 4 suddenly rises due to the bottom of the dash panel 5, and then the crush deformation of the vehicle body ends and the deceleration becomes zero. The occupant deceleration characteristic d in this comparative example rises more slowly than the vehicle body deceleration characteristic c, and the degree of increase gradually increases. Then, even in a region where the extension of the seat belt that restrains the occupant reaches the maximum and the occupant deceleration becomes the maximum, since the vehicle body deceleration is high as described above, the reaction force to the occupant by the seat belt becomes extremely large.

On the other hand, in the case of the deceleration characteristics a and b of the vehicle body and the occupant according to the first embodiment, the vehicle body deceleration characteristic a is the same as that of the crash boxes 26 and 26 and the frame-side impact absorbing portions 53 and 53 as described above. When the crushing deformation starts, the seat belt rises steeply, whereby the seat belt is extended relatively early, and the occupant deceleration rises without much delay from the vehicle body deceleration (see the occupant deceleration characteristic b). Immediately before the elongation of the seat belt is maximized, as described above, the crash boxes 26, 26 and the
3 and 53 are finished, and then the front frame 5
When the sliding of 0,50 is started, the vehicle body deceleration temporarily drops, and the seatbelt elongation of the seatbelt is maximized in the region where the vehiclebody deceleration falls, so that the occupant receives the seatbelt. Can be greatly reduced as compared with the comparative example.

As described above, in the first embodiment, the front frames 50, 50 are provided at the beginning of the frontal collision of the vehicle.
The vehicle body deceleration stably and steeply rises by the crushing deformation of the shock absorbing portions 52, 52 while keeping the and the rear frames 51, 51 in a fixed state, and the front frames 50, 51 immediately after the crushing deformation are completed. 50 is the rear frame 5
Since the vehicle body is depressed by sliding with respect to the vehicle seats 51, 51, the impact load acting on the occupant due to the reaction force from the seat belt at the time of collision can be reliably reduced.

The rear bolt holes 58 and the slits 59 of the rear frame 51 may be integrally formed so as to be continuous with each other as shown in FIG. In this embodiment, projections 59a, 59a are provided on the upper edge and the lower edge of the slit 59 so as to face each other from the portions adjacent to the shaft of the rear bolt 55, and the projections 59a, 59a are formed. The above-described holding unit may be used.

Further, in the case where the bolt hole 58 and the slit 59 are formed integrally as described above, FIG.
As shown in the figure, the vertical dimension of the slit 59 in the vehicle body is made shorter than the shaft diameter of the bolt 55, and step portions 59b, 59b are formed between the bolt hole 58 and the slit 59, and the step portions 59b, 59b are formed. May be used as the holding unit described above. In this case, since the shaft of the bolt 55 is sandwiched between the upper edge and the lower edge of the slit 59 when the front frame 50 slides, a sliding resistance can be given to the front frame 50,
This sliding resistance can be increased or decreased by the size of the slit 59 in the vertical direction of the vehicle body. Therefore, by changing the shape of the upper edge portion and the lower edge portion of the slit 59, the above-described vehicle deceleration characteristics can be changed. For example, the closer the both edges are, the longer the descent time of the vehicle deceleration becomes. it can.

Further, by applying the above-described configuration in which the size of the slit 59 in the vertical direction of the vehicle body to be shorter than the shaft diameter of the bolt 55 is applied to the above-described embodiment, as shown in FIG. The front edge of the slit 59 may be positioned at a predetermined distance away from the rear edge of the vehicle body toward the rear of the vehicle body.

In the first embodiment, a plurality of sets of bolts 55, 55,... And nuts 56, 55,.
Although the front frame 50 and the rear frame 51 are fastened to each other, the present invention is not limited to this. For example, the front frame 50 and the rear frame 51 may be fastened using a set of bolts 55 and nuts 56.

(Embodiment 2) FIG. 9 shows a front vehicle body structure of an automobile according to Embodiment 2 of the present invention, and corresponds to FIG. The structure of the front portion of the vehicle body according to the second embodiment is substantially the same as that of the first embodiment, and the front and rear frames 5 of the front side frame 11 are different.
Since the configurations of the coupling portions 0 and 51 are only partially different, the same portions are denoted by the same reference numerals and only different portions will be described below. That is, in the second embodiment, the pin member 6 that fixes the front frame 50 to the rear frame 51 is used.
5 and a lever member (release member) 66 for releasing the pin member 65 from the frames 50 and 51 during a frontal collision of the vehicle.

More specifically, at a portion where the rear end of the front frame 50 and the front end of the rear frame 51 overlap, a pin member 65 that penetrates the frames 50 and 51 in the vehicle width direction is provided. Is provided. Both ends of the pin member 65 are inserted into the inner and outer walls of the frames 50 and 51, respectively.
Are pinned in a fixed state. The pin portion 69 on the inner side of the vehicle body is integrally formed with a flange 68 which contacts the outer surface of the side wall portion of the rear frame 51 to prevent the pin member 65 from coming out of the vehicle body. On the other hand, the pin portion 69 on the outer side of the vehicle body has a pin member 6 similar to the flange 68 on the outer periphery of a portion corresponding to the formation portion of the flange 68 on the pin portion 69 on the inner side of the vehicle body.
5 is formed with a U-shaped cross-sectional groove into which a C-shaped fastener 79 for preventing the inward movement of the vehicle body is fitted.

Further, the pin portion 69 on the outer side of the vehicle body is provided with a groove 70 having a V-shaped cross section over the entire outer periphery of a portion surrounded by the pin member through hole 67 of the rear frame 51. Are formed in the groove 70 when an axial tensile load is applied as described later. A small diameter portion 71 having a relatively small diameter is formed between the two pin portions 69, 69 so as to connect the pin portions 69, 69 to each other.

When fixing the front frame 50 and the rear frame 51, first, as in the first embodiment, the corresponding pin member through holes 67, 67 of both frames 50, 51 are connected to each other. The positions of the two frames 50 and 51 are adjusted such that the numbers overlap. Next, the pin member 65 is inserted into each of the pin member through holes 67 of the front and rear frames 50 and 51 from the inside of the engine room 1 to the outside of the vehicle body, and further the pin portion 6 on the outside of the vehicle body is inserted.
This is performed by fitting the fastener 79 into the groove having the U-shaped cross section in FIG.

A slit 72 extending rearward of the vehicle body continuously with the pin member through hole 67 is provided in a wall portion of the rear frame 51 on the vehicle body inner side. This slit 72
Of the pin member 65 in the vertical direction of the vehicle body
It is slightly larger than 1. Further, the pin member 65 on the inner wall portion of the rear frame 51 on the vehicle body side.
A substantially L-shaped lever member 66 that engages with the power plant 4 that retreats at the time of a frontal collision of the vehicle and separates the pin member 65 from the front and rear frames 50 and 51.
Is provided. The lever member 66 has a substantially U-shaped bracket 7 that opens inward of the vehicle body in a state where the two arm portions 75 and 76 are both arranged to extend substantially horizontally.
A support shaft (rotating shaft) 78 extending in the vehicle body vertical direction with respect to 7
Supported by

The two arm portions 7 of the lever member 66
5 and 76, the distal end side of the first arm portion 75 is rotatably connected to a convex portion formed by projecting inward from the vehicle body inward from the vehicle body inward end of the pin member 65. The distal end side of the two-arm portion 76 extends inward of the vehicle body so as to overlap with the power plant 4 when viewed from the vehicle front-rear direction. The overlapping portion of the power plant 4 with the second arm portion 76 and the tip end side of the second arm portion 76 are separated from each other by a predetermined distance (for example, 30 mm to 40 mm) in the vehicle longitudinal direction. The power plant 4 does not come into contact with the second arm portion 76 due to the swing of the power plant 4.

When a compressive load in the vehicle front-rear direction acts on the front side frame 11 configured as described above, the pin portions 69, 69 provided on both ends of the pin member 65 connect the front frame 50 to the front frame 50. It is fixed to the rear frame 51. On the other hand, when the power plant 4 retreats at the time of a frontal collision of the automobile, the power plant 4 engages with the second arm portion 76 of the lever member 66 and
The arm portion 76 is rotated around the support shaft 78, whereby the first arm portion 75 of the lever member 66 also
, A tensile load acts on the pin member 65 connected to the first arm 75. Then, the pin member 65 is broken at the groove 70 of the pin portion 69, and the portion of the pin portion 69 on the outer side of the vehicle body and the fastener 79 are connected to the pin member 65.
From the frames 50 and 51. The small-diameter portion 71 of the pin member 65 broken as described above moves to the slit 72 of the rear frame 51 and can retreat along with the front frame 50 along the slit 72, whereby the rear side of the front frame 50 Frame 51
Is released from the fixed state. That is, in the second embodiment, the timing at which the front frame 50 starts sliding can be set by the distance between the second arm portion 76 and the power plant 4 in the vehicle longitudinal direction.

Next, the deformation of the front side frames 11, 11 when the vehicle has a frontal collision will be described in detail.

First, as in the first embodiment, in the initial stage of a collision, the shock absorbing portions 52, 52 start crushing and deforming, while the front frames 50, 50 and the rear frame 51 of the front side frames 11, 11 start. , 51 are fixed by the pin members 65 as described above, so that at this stage, the sliding of the front frames 50, 50 does not occur, and only the crushing deformation of the shock absorbing portions 52, 52 occurs, and a relatively large body reduction occurs. Speed occurs.

Subsequently, when the crushing deformation of the shock absorbing portions 52, 52 is completed, an impact load is directly applied to the power plant 4 via the radiator, the intake manifold and the like, and the power plant 4 Retreat.
The second arm portion 76 of the power plant 4
Is engaged with the second arm portion 76, and the lever member 66 rotates around the support shaft 78. As a result, the pin member 65 is broken at the groove 70 of the pin portion 69 and the rear frame 5 of the front frame 50 is broken.
1, the sliding of the front frame 50 can be started during the collision in the same manner as in the first embodiment.

The groove 70 having a V-shaped cross section of the pin member 65 may be provided in the small diameter portion 71 of the pin member 65. In this case, the small diameter portion 7 is formed by the tensile load.
1 is separated into the vehicle body inner side and the outer side with respect to the groove.

As described above, in the second embodiment, the pin member 65 is detached from the front side frame 11 by the power plant which moves backward in the event of a frontal collision of the vehicle. The timing of sliding with respect to the side frame 51 can be easily and reliably set.

(Embodiment 3) FIGS. 10 and 11 show a front body structure of an automobile according to Embodiment 3 of the present invention. The structure of the front part of the vehicle body according to the third embodiment is substantially the same as that of the first embodiment,
Since the configuration of 0 is only partially different, the same portions will be denoted by the same reference numerals and only different portions will be described below. That is, in the third embodiment, as shown in FIG. 10, the side member portions 33, 33 of the perimeter frame 30 are divided into front frames (front members) 80, 80 and rear frames (rear members) 81, 81. I do. A pin member 82 for fixing the front frame 80 to the rear frame 81
In the same manner as in the second embodiment, the pin member 82 is connected to both frames 80 and 81 during a frontal collision of the vehicle.
A lever member 83 is provided to be disengaged.

More specifically, the perimeter frame 30
The front end side of the front side frame 11, 1
1 is located just below the rear ends of the frame-side impact absorbing portions 53, 53, and is attached to the lower side walls of the front frames 50, 50 by the same mounting brackets 36, 36 as in the first embodiment. On the other hand, both side member portions 33, 33 of the perimeter frame 30 have front frames 80, 80 and a rear frame 81, between the bent portion when viewed from the vehicle width direction and the suspension cross member portion 34. 81. The outer dimensions of the cross section of the front frames 80, 80 are the rear frames 81, 81.
Of the front frame 8
The rear end side of 0,80 is relative to the rear side frames 81,81.
The two members 80, 80, 81, 81 are fixed in a state where they are slidably fitted in the vehicle longitudinal direction. Further, the rear ends of the front frames 80, 80 overlap with the front ends of the rear frames 81, 81 by a predetermined distance when viewed from the vehicle up-down and vehicle width directions.

Next, FIG. 11 is an enlarged view of a vertical cross-sectional structure in the vicinity of the connecting portion for fixing the front frame 80 and the rear frame 81 of the perimeter frame 30 as described above. It will be described based on the following. In the overlapping portions of the front and rear frames 80 and 81, the upper walls of the frames 80 and 81 are fixed to each other by a pin member 82 that penetrates in the vertical direction of the vehicle body, while the lower walls are mutually It is fixed by spot welding (the welding site is indicated by the symbol S in the figure). The pin member 82 has a flange formed at the lower end thereof to contact the inner surface of the upper wall of the front frame 80, and a flange formed at the upper end thereof to contact the outer surface of the upper wall of the rear frame 81. I have.

Further, behind the pin member 82 on the upper wall portion of the rear frame 81, the pin member 8 is engaged with the power plant 4 which retreats at the time of a frontal collision of an automobile.
A substantially L-shaped lever member 83 for detaching the front and rear frames 2 from the front and rear frames 80 and 81 is provided. The lever member 83 has substantially the same shape as that of the second embodiment,
The bracket 85 fixed to the rear frame 81 of the perimeter frame 30 is supported by a support shaft 84 extending in the vehicle width direction.

The two arm portions 8 of the lever member 83
6 and 87, the first arm portion 8 extending in the vehicle longitudinal direction.
6 is rotatably connected to a convex portion formed by projecting upward from the upper end of the pin member 82 to the upper side of the vehicle body, while the distal end side of the second arm portion 87 is viewed from the vehicle longitudinal direction. , And extends above the vehicle body so as to overlap with the power plant 4. The overlapping portion of the power plant 4 with the second arm portion 87 and the distal end side of the second arm portion 87 are separated by a predetermined distance in the longitudinal direction of the vehicle body as in the first embodiment.

When a compressive load in the vehicle longitudinal direction is applied to the perimeter frame 30 configured as described above, the pin member 82 penetrating the upper wall portion of the front and rear frames 80 and 81 and the lower wall The welded portion S of the portion fixes the front frame 80 to the rear frame 81.

As in the case of the front side frame 11 in the second embodiment, when the power plant 4 retreats at the time of a frontal collision of the vehicle, the lever member 83 rotates around the support shaft 84 and the first arm portion 86 A tensile load is applied to the connected pin members 82 in the upward direction of the vehicle body to deform the lower flange portion of the pin members 82 so that the pin members 82 are disengaged from the front and rear frames 80 and 81. As a result, the compression load acting on the front end of the perimeter frame 30 causes
The welding portions S of the lower walls of the front and rear frames 0 and 81 are separated from each other, and the fixed state of the front frame 80 to the rear frame 81 is released, so that the front frame 80 retreats.

That is, in the third embodiment, the timing at which the front frame 80 starts sliding can be set based on the distance between the second arm 87 and the power plant 4 in the vehicle longitudinal direction, as in the second embodiment. It has become.

Next, the front side frames 11, 11 and the perimeter frame 3 when the vehicle collides from the front are described.
The deformation of 0 will be described in detail.

First, as in the first and second embodiments, in the early stage of the collision, the shock absorbing portions 52, 52 start crushing and deforming.
On the other hand, the load for releasing the fixed state of the front side frames 11, 11 with respect to the front frames 50, 50 on the rear frames 51, 51 is, as described in the first embodiment, the crushing deformation of the shock absorbing parts 52, 52. Is set to the load acting on the front side frames 11, 11 after the completion of the above, at this stage, the front side frames 50,
The sliding of 50 does not occur, and the deceleration of the vehicle body largely rises only by the crushing deformation of the shock absorbing portions 52, 52.

The perimeter frame 30 also has its front end mounted at a position corresponding to the rear end of the shock absorbing portions 52, 52, and the front and rear frames 80, 81 are connected to the pin member 82. And by being fixed by welding, the front side frame 80 does not slide, and at this time, the front side frames 11, 11 and the perimeter frame 30
1, 30 have high rigidity as a whole.
Therefore, at the stage of the crushing deformation of the shock absorbing portions 52, 52, the front frames 50, 50, 8 of the front side frames 11, 11 and the perimeter frame 30, respectively.
0, 80 does not start sliding, and the vehicle body deceleration rises relatively large only by the crush deformation of the shock absorbing portions 52, 52.

Subsequently, when the crushing deformation of the shock absorbing portions 52, 52 is completed, the fixed state of the front side frames 11, 11 is released as described in the first embodiment. At substantially the same time, the power plant 4 that retreats in the same manner as in the second embodiment makes contact with the second arm portion 87 of the lever member 83 to separate the pin member 82 from the front and rear frames 80, 81, Immediately after that both frames 8
The welding portions S on the lower wall portions of the 0 and 81 are separated. Therefore, when the fixed state at the joint of the front side frames 11, 11 is released, the perimeter frame 3
0 is also released from the fixed state by the connecting portion of the front side frames 11, 11 and the perimeter frame 30.
Of each of the front frames 50, 50, 80, and 80 starts sliding.

As described above, in the third embodiment, the front side frame 11 and the perimeter frame 30 are integrally formed to have high rigidity as a whole at the initial stage of the frontal collision of the vehicle as described above. The same operation and effect as in the first embodiment can be obtained for the vehicle body structure described above.

(Other Embodiments) The present invention is not limited to the first to third embodiments, but includes other various embodiments. That is, the structure of the connecting portion of the first and second embodiments may be applied to the perimeter frame 30, and the structure of the connecting portion of the third embodiment may be applied to the front side frames 11 and 11. , May be appropriately combined.

[0085]

As described above, according to the vehicle body front structure according to the first aspect of the present invention, the front side frame is fitted to the front member so that the front member can slide in the vehicle longitudinal direction. The front side member starts to slide with respect to the rear member during the deformation of the front side frame during the frontal collision of the vehicle, so that the vehicle deceleration at the time of the frontal collision of the vehicle is reduced. By changing as intended, the impact load on the occupant can be reliably reduced.

According to the second aspect of the invention, the range in which the vehicle body deceleration is temporarily lowered during the deformation of the front side frame is appropriately set by regulating the sliding distance of the front side member with respect to the rear side member. Can be.

According to the third aspect of the present invention, the front member can be securely fixed to the rear member by the fastening member, while at the time of a frontal collision of the vehicle, the shaft of the fastening member is moved rearward along the slit along the vehicle body. By moving, the front member can be slid with respect to the rear member.

According to the fourth aspect of the present invention, the two members can be securely fixed by the pin member penetrating the front member and the rear member, and at the time of a frontal collision of the vehicle, the pin member is separated from the front member or the rear member by the release member. By detaching from the side members, the fixed state of both members can be reliably released.

According to the fifth aspect of the present invention, at the time of a frontal collision of the vehicle, the lever member is rotated by the retreat of the power plant, so that the pin member can be reliably detached.

According to the sixth aspect of the invention, the vehicle body rigidity of the front portion of the automobile can be improved as a whole by the sub-frame so that the same effect as the first aspect of the invention can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a front portion of a vehicle body according to an embodiment of the present invention.

FIG. 2 is a bottom view showing the structure of the front part of the vehicle body.

FIG. 3 is a perspective view showing the structure of the front part of the vehicle body as viewed from above.

FIG. 4 is an enlarged view showing the vicinity of a coupling portion in FIG. 1;

FIG. 5 is a sectional view taken along line AA in FIG. 4;

FIG. 6 is a diagram corresponding to FIG. 1, showing a state of a front portion of the vehicle body at the time of a frontal collision;

FIG. 7 is a characteristic diagram showing a change in vehicle deceleration with respect to a vehicle crush amount.

FIG. 8 is an enlarged view of a bolt hole and a slit and a diagram showing a modified example thereof.

FIG. 9 is a diagram corresponding to FIG. 5 according to a second embodiment of the present invention.

FIG. 10 is a diagram corresponding to FIG. 1 according to a third embodiment of the present invention.

11 is an enlarged view showing a cross-sectional structure in the vicinity of a coupling portion of the perimeter frame in FIG.

FIG. 12 is a plan view showing a vehicle body front structure of a conventional automobile.

FIG. 13 is a diagram corresponding to FIG. 12, showing a state of a front portion of the vehicle body after a frontal collision;

[Explanation of symbols]

Reference Signs List 4 power plant 11 front side frame 30 perimeter frame (sub frame) 50 front frame (front member of front side frame) 51 rear frame (rear member of front side frame) 52 shock absorber 55, 56 bolt, nut (fastening) 58) Bolt hole (through hole) 59 Slit 65 Pin member 66 Lever member (removal member) 75 First arm section 76 Second arm section 78 Support shaft (rotating shaft) 80 Front frame (front member of subframe) 81 Rear frame (rear member of subframe)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sakae Terada 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Hiroshi Hanada 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Yuko Fujii 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Pref.

Claims (6)

[Claims] 1. A front vehicle body structure comprising a pair of front side frames each extending in the vehicle front-rear direction on both left and right sides of a front portion of the vehicle body and having a shock absorbing portion provided on a front end side. A front member having the shock absorbing portion, and a rear member fitted with a rear end of the front member so as to be slidable in the vehicle longitudinal direction, and fixing the front member to the rear member. A coupling portion, wherein the coupling portion is configured to release the fixed state of the front and rear members after the impact energy absorbing load in the impact absorbing portion reaches a set value when the vehicle collides from the front. A front body structure of an automobile, characterized in that it is made. 2. The device according to claim 1, further comprising a restricting means for restricting retraction of the front member so that a sliding distance of the front member relative to a rear member is equal to or less than a set distance. Front body structure of the car. 3. The connecting member according to claim 2, wherein the connecting portion includes a fastening member that fastens the front member and the rear member, a through hole through which a shaft of the fastening member passes through the rear member, and a vehicle body having the through hole. A front vehicle body structure for an automobile, comprising: a slit provided in the vicinity of the rear and elongated in the vehicle front-rear direction. 4. The pin according to claim 2, wherein a power plant is disposed between the pair of front side frames, and the connecting portion penetrates a front member and a rear member to fix both members. A front body structure of an automobile, comprising: a member; and a detachment member that engages with the power plant that retreats at the time of a frontal collision of the automobile and detaches the pin member from the front member or the rear member. 5. The detachable member according to claim 4, wherein the detachable member is rotatably supported by the front side frame, and is different from the support portion when viewed along a direction in which the rotation axis extends. A lever member having at least two extended arm portions, wherein a distal end side of a first arm portion of the lever member is connected to the pin member, and a distal end side of a second arm portion is connected to the power plant from the front side frame. A front body structure of an automobile, wherein the front body structure is positioned so as to protrude to the side and to be spaced away from the power plant by a predetermined distance. 6. The sub-frame according to claim 1, wherein a sub-frame extending in a vehicle front-rear direction is disposed below the pair of front side frames, and the sub-frame includes a front member and a rear end side of the front member. A rear member fitted slidably in the front-rear direction of the vehicle body, and a coupling portion for fixing the front member to the rear member; Wherein the fixed state of the front and rear members is released when the fixed state of the connecting portion is released.